Document finisher modules are known. Xerox has launched the Base Finisher Module, a finishing device with stacking (with and without offsetting), stapling (portrait, landscape and dual), and dual finishing (unload while run) capabilities. As depicted in FIG. 1, the architecture consists of an input transport 10, compiler 50 and a stack tray 60 with a full capacity of 3,000 sheets. This capacity decreases as stack flatness deteriorates due to any of paper curl, waviness and staple thickness. The uneven stack growth caused by staple thickness creates the following problem and the need for this invention.
First, as to stack quality and productivity, the stack flatness rapidly deteriorates due to the cumulative effect of the staple thickness, significantly reducing the number of sheets and sets that can be stacked reliably. Currently small stapled sheets comprising 15 sheets or less are limited to low number of sets to minimize shutdowns.
Second, as to handling, the stack of stapled sets is unstable, making it very difficult to handle, store and package.
Thus, there is a need for the present invention.